Recently, liquid crystal televisions using liquid crystal displays have been actively developed. Further, as an approach for achieving a higher function of liquid crystal televisions, development of a stereoscopic image display apparatus using a liquid crystal display is being advanced.
A plurality of types of schemes are proposed for this stereoscopic image display apparatus using the liquid crystal display apparatus. For example, a parallax barrier scheme, a lenticular lens scheme and a switch backlight scheme are known. These schemes provide an advantage that a viewer does not need dedicated glasses to view video images from a display apparatus. However, the parallax barrier scheme and the lenticular lens scheme have a problem that, the horizontal resolution decreases and therefore the resolution of image display decreases. The switch backlight scheme has a problem in that flickering of images occur.
Further, as a scheme using dedicated glasses, a shutter glass scheme is known. This scheme provides an advantage of widening a display view angle of an image display apparatus without decreasing the resolution. However, this scheme has problems that flickering of display images occur, the brightness of a display screen decreases and a time lag is produced between images visible to left and right eyes, and therefore natural images cannot be provided for the viewer.
Further, a stereoscopic image display apparatus is recently proposed which uses novel optical units to provide stereoscopic images. For example, Japanese Patent Application Laid-Open No. 10-63199 discloses a stereoscopic image display apparatus which does not require dedicated glasses by using two polarization filters which are such novel optical units.
With the stereoscopic image display apparatus disclosed in Japanese Patent Application Laid-Open No. 10-63199, a right eye polarization filter and a left eye polarization filter having the polarization directions orthogonal to each other are arranged in the front left and right of a light source. Further, respective lights transmitted through these filters are converted into substantially parallel lights by a Fresnel lens and are radiated to a liquid crystal display. Furthermore, linear polarization filter lines in which polarization directions are orthogonal to each other are alternately arranged per horizontal line of polarization filters on the both surfaces of this liquid crystal display, and opposing linear polarization filter lines on the light source side and viewer side have polarization directions which are orthogonal. Still further, the liquid crystal panel of the liquid crystal display is configured to alternately display right eye video information and left eye video information per horizontal line according to transmittance lines of two polarization filters.
That is, all horizontal lines of a display screen are divided into odd lines and even lines and left eye and right eye images are displayed on the respective lines to sort these left eye and right eye images for the left and right eyes of the viewer by means of novel optical units and display stereoscopic images.
This apparatus does not cause stereoscopic images to deteriorate even if a viewing position of a viewer is moved more or less to the left or right. This apparatus can also avoid a phenomenon in which a horizontal resolution decreases by half which is the problem of the parallax scheme and the lenticular lens scheme.
Further, Japanese Patent Application Laid-Open No. 2006-284873 discloses a stereoscopic image display apparatus which uses novel retarders as novel optical units which have two different areas which make polarizing axes of incident lights orthogonal to each other. This stereoscopic image display apparatus has a liquid crystal display which displays a right eye image and a left eye image on different areas, and the retarders corresponding to left and right image display areas, and provides stereoscopic images by projecting parallax images toward the viewer. Further, this stereoscopic image display apparatus is known to display images of a wider view angle.